1. Field of the Invention
This invention relates to semiconductor devices, and, more particularly, to a semiconductor device having conductive vias.
2. Description of Related Art
With the constantly progressing of electronic industry, more and more electronic components can be integrated in a semiconductor device, and as a compact trend of electronic products, the volume of a semiconductor device becomes smaller and smaller. A 3D package technique is therefore developed, which configures a plurality of chips in a semiconductor device. In order to achieve the requirement of stacking those chips on each other, a so-called Through Silicon Vias (TSV) technique is developed, which forms a plurality of passing-through hole in a silicon substrate. Therefore, the processing speed of the semiconductor device can be increased, and the power dissipation can be greatly reduced.
FIG. 1 illustrates a schematic sectional view of a semiconductor device 1 according to the prior art. The semiconductor device 1 includes a silicon substrate 10, an insulating layer 12, an Under Bump Metallurgy (UBM) 13, and a plurality of conductive bumps 14. The silicon substrate 10 has a plurality of through silicon vias 11. The insulating layer 12 is formed on the silicon substrate 10 and exposes end portions of the through silicon vias 11. The UBM 13 is formed on the end portions of the through silicon vias 11. The conductive bumps 14 are formed on the UBM 13.
However, the conductive bumps 14 are soldered on the UBM 13 of the silicon substrate 10 via a reflowing method, and the remaining stresses due to the heat will concentrate on the interface between the conductive bumps 14 and the through silicon vias 11 as a stresses concentration 15 in FIG. 1. The stresses concentration may result in a crack after the conductive bumps 14 are subsequently on board, thereby decreasing the reliability of the semiconductor device 1 and the yield of product.
Therefore, how to overcome the mentioned problems of the prior art is substantially an issue desirably to be solved.